Field
This disclosure relates to devices and methods for isolating a treatment region from fluid pressure, and more specifically, to providing medical devices that adaptably approximate the cross-sectional profile of the vasculature in an area of the vasculature having branch vessels and/or an irregular configuration.
Discussion of the Related Art
Treatment of various portions of the vasculature may require the installation of one or more medical devices. In this regard, a medical device can be any device or structure configured to provide and/or support a therapeutic use in the vasculature. Commercially available devices generally possess specific requirements with regard to the dimensions and configuration of the region to be treated. However, the cross-sectional profile and configuration of the primary vessel being treated, the locations at which branch vessels join the primary vessel with respect to the treatment site, and the configuration and condition of branch vessels may vary considerably on a patient-by-patient basis in a manner that can significantly affect patient eligibility for treatment with available devices. For example, in an abdominal aorta with an aneurysm, the distance between the renal arteries and the aneurysm and the length of normal-diameter iliac artery available for proximal and distal attachment can significantly affect patient eligibility for available stent devices. Angulation of the attachment site between the renal arteries and the aneurysm can also present significant limitations to treatment with commercial devices. The status and size of the iliofemoral arteries and their capacity to accommodate insertion of medical devices may impose a further limitation on a patient's eligibility for treatment with a particular medical device. Variations in the anatomical limitations presented by individual patients in combination with the limitations of available devices impose a significant limitation on patient eligibility for treatment with implantable medical devices.
For example, FIGS. 1A-1D illustrate a range of possible configurations of an abdominal aorta. FIG. 1A illustrates a vasculature 101A comprising an abdominal aorta without an aneurysm as well as major branch arteries, including the renal arteries 110, the superior mesenteric artery (“SMA”) 111, the celiac artery 112, the common iliac arteries 113, the external iliac arteries 114, and the internal iliac arteries 115. FIG. 1B illustrates a vasculature 101B having a “textbook” abdominal aortic aneurysm (“AAA”) 102 with a length of normal aorta proximal (closer to the heart) to the site of the aneurysm and distal (further from the heart) to the renal arteries, a region referred to as the infrarenal aortic neck 103. An AAA as illustrated in FIG. 1B may be treated with any of a number of commercially available implantable medical devices that require a length of normal infrarenal aorta for proximal attachment of the device within the vasculature.
FIG. 1C illustrates a vasculature 101C having a pararenal AAA, wherein the aorta lacks a length of normal aorta between the aneurysm and the renal arteries. A patient having a pararenal AAA may be ineligible for treatment with various commercially available devices that require a length of normal infrarenal aorta for proximal attachment and implantation. Alternatively, a patient with a pararenal AAA can be treated using chimney or sandwich graft approaches. These approaches may increase a risk of leakage around the devices at the treatment site or of device migration.
FIG. 1D illustrates a vasculature 101D having an angulated infrarenal aortic neck 104. As for a pararenal AAA, an abdominal aorta with angulation of the infrarenal aortic neck presents significant challenges for treatment with implantable medical devices, as most commercially available medical devices may be unable to conform to the cross-sectional profile of the vasculature. Moreover, the flow through the lumens defined by such medical devices may be suboptimal because the cross-sectional profile created by the medical devices at the treatment site may not substantially approximate the cross-sectional profile of the vasculature.
Thus, a need exists for devices that are adaptable to a variety of anatomical configurations to expand the scope of patient eligibility for treatment and to enhance the performance of medical devices implanted into a body lumen, particularly in patients having irregular or tortuous anatomies.